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Subject[PATCH 0/6] kexec: A new system call to allow in kernel loading
Date
Current proposed secureboot implementation disables kexec/kdump because
it can allow unsigned kernel to run on a secureboot platform. Intial
idea was to sign /sbin/kexec binary and let that binary do the kernel
signature verification. I had posted RFC patches for this apparoach
here.

https://lkml.org/lkml/2013/9/10/560

Later we had discussion at Plumbers and most of the people thought
that signing and trusting /sbin/kexec is becoming complex. So a
better idea might be let kernel do the signature verification of
new kernel being loaded. This calls for implementing a new system call
and moving lot of user space code in kernel.

kexec_load() system call allows loading a kexec/kdump kernel and jump
to that kernel at right time. Though a lot of processing is done in
user space which prepares a list of segments/buffers to be loaded and
kexec_load() works on that list of segments. It does not know what's
contained in those segments.

Now a new system call kexec_file_load() is implemented which takes
kernel fd and initrd fd as parameters. Now kernel should be able
to verify signature of newly loaded kernel.

This is an early RFC patchset. I have not done signature handling
part yet. This is more of a minimal patch to show how new system
call and functionality will look like. Right now it can only handle
bzImage with 64bit entry point on x86_64. No EFI, no x86_32 or any
other architecture. Rest of the things can be added slowly as need
arises. In first iteration, I have tried to address most common use case
for us.

Any feedback is welcome.

Vivek Goyal (6):
kexec: Export vmcoreinfo note size properly
kexec: Move segment verification code in a separate function
resource: Provide new functions to walk through resources
kexec: A new system call, kexec_file_load, for in kernel kexec
kexec-bzImage: Support for loading bzImage using 64bit entry
kexec: Support for Kexec on panic using new system call

arch/x86/include/asm/crash.h | 9 +
arch/x86/include/asm/kexec-bzimage.h | 12 +
arch/x86/include/asm/kexec.h | 43 ++
arch/x86/kernel/Makefile | 2 +
arch/x86/kernel/crash.c | 585 +++++++++++++++++++++++++++
arch/x86/kernel/kexec-bzimage.c | 420 +++++++++++++++++++
arch/x86/kernel/machine_kexec_64.c | 60 +++-
arch/x86/kernel/purgatory_entry_64.S | 119 ++++++
arch/x86/syscalls/syscall_64.tbl | 1 +
include/linux/ioport.h | 6 +
include/linux/kexec.h | 57 +++
include/linux/syscalls.h | 3 +
include/uapi/linux/kexec.h | 4 +
kernel/kexec.c | 731 ++++++++++++++++++++++++++++++----
kernel/ksysfs.c | 2 +-
kernel/resource.c | 108 +++++-
kernel/sys_ni.c | 1 +
17 files changed, 2074 insertions(+), 89 deletions(-)
create mode 100644 arch/x86/include/asm/crash.h
create mode 100644 arch/x86/include/asm/kexec-bzimage.h
create mode 100644 arch/x86/kernel/kexec-bzimage.c
create mode 100644 arch/x86/kernel/purgatory_entry_64.S
--
1.7.7.6



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